Alternative fuel comprising combustible solids and by-products or waste material from industrial processes

ABSTRACT

An alternative fuel composition and methods of preparing and using the composition is provided. The alternative fuel can comprise coal, or another combustible solid, and one or more components selected from a group consisting of sugar solutions, tall oil, black liquor, vegetable oils, animal fats, triglycerides, methyl esters, ethyl esters, glycerin and fatty acids.

TECHNICAL FIELD

This invention relates to alternative fuels comprising by-products orwaste material from industrial processes and methods of using the fuels.More particularly, this invention concerns alternative fuels comprisingliquid hydrocarbons derived from biomass and combustible solids. Thebiomass liquid hydrocarbons can include sugar solutions, tall oil, blackliquor, vegetable oils, animal fats, triglycerides, methyl esters, ethylesters glycerin and fatty acids. The liquid hydrocarbon is mixed withcoal or other combustible solids to prepare the alternative fuel.

BACKGROUND OF THE INVENTION

The current US economy is dominated by technologies that rely on fossilenergy (coal, petroleum, and natural gas) to produce fuels. Biomasspresents a promising renewable energy source that could provide analternative to the use of fossil resources. Biomass includes crops,trees, grasses, crop residues, forest residues, animal wastes, andmunicipal wastes. There are many reasons to increase the use biomass forenergy, including lessening dependence upon foreign oil, utilizing greenchemistries from a renewable source, creating less toxic pollution, andimproving the domestic agricultural economy.

A fuel product formed from vegetable oil and dried cellulosic powder isdisclosed in U.S. Pat. No. 6,818,027 B2 and Published Patent ApplicationNo. 2005/0055873 A1.

A fuel product formed by homogenizing, heating, pressurizing andremoving water from organic waste products of industrial processes andthen separating a selected constituent from the product into a wastestream and blending the waste stream with a fuel is disclosed inPublished Patent Application Publication No. 2005/0142250 A1.

U.S. Pat. No. 6,890,451 B2 discloses an anti-icing or deicing fluidcomprising by-products of triglyceride processing and its application tosurfaces including particulate materials such as coal. A method ofpreventing the agglomeration of coal in subfreezing temperaturescomprising applying an anti-agglomerating amount of by-product glycerincontaining up to 5 percent methanol by weight to the coal is disclosedin U.S. Pat. No. 7,108,800. A method of preventing the agglomeration ofcoal in subfreezing temperatures comprising applying ananti-agglomerating amount of by-product sugar solution to the coal isdisclosed in U.S. Pat. No. 6,878,308 B2.

SUMMARY OF THE INVENTION

This invention relates to a novel and cost effective fuel and methods ofpreparing and using the fuel. The fuel comprises biomass liquidhydrocarbons mixed or blended with existing fuels such as coal and/orother combustible solids. Some of the biomass hydrocarbon liquids ofthis invention are by-products of current processes. For example, fattyacids and glycerin are by-products of a biodiesel manufacturing process.

Accordingly, in an embodiment, this invention is an alternative fuelcomprising one or more combustible solids and one or more liquidhydrocarbon components selected from a group consisting of sugarsolutions, tall oil, black liquor, vegetable oils, animal fats,triglycerides, methyl esters, ethyl esters, glycerin and fatty acids,provided that when the liquid hydrocarbon component is vegetable oil,the combustible solid is other than a cellulosic powder and furtherprovided that when the combustible solid is coal, the liquid hydrocarboncomponent is other than sugar solutions.

In another embodiment, this invention is method of preparing aalternative fuel comprising applying one or more liquid hydrocarboncomponents selected from a group consisting of sugar solutions, talloil, black liquor, vegetable oils, animal fats, triglycerides, methylesters, ethyl esters, glycerin and fatty acids to one or morecombustible solids, provided that when the liquid hydrocarbon componentis vegetable oil, the combustible solid is other than a cellulosicpowder and further provided that when the combustible solid is coal, theliquid hydrocarbon component is other than sugar solutions.

DETAILED DESCRIPTION OF THE INVENTION

The invention uses biomass liquids such as sugar solutions, tall oil,black liquor, vegetable oils, animal fats, triglycerides, methyl esters,ethyl esters, glycerin and fatty acids mixed with coal or othercombustible solids to create alternative fuels. The sugar solutions,vegetable oils, animal fats, triglycerides, methyl esters, glycerin andfatty acids described herein are “green”, i.e. non-hazardous, non-toxic,biodegradable, environmentally friendly, and/or derived from renewablesources.

“Combustible solids” means any solid combustible material which can bemixed with one or more biomass liquids as described herein to preparethe alternative fuel of the invention. In an embodiment, the combustiblesolid is selected from coal, wood chips, coke, and garbage. In anotherembodiment, the combustible solid is coal. “Coal” includes fine coalfrom stockpiles, fine coal from impoundments, run of mine coal washed,run of mine coal unwashed and waste coal. Coke is derived from coal.Garbage includes municipal and/or industrial garbage.

“Sugar solutions” refers to by-products of sugar beet or sugar caneprocessing which can comprise one or more components selected fromraffinose, glutamine, betaine, lactate, glucose and/or fructose. Othercomponents can include sodium, potassium, chloride, nitrate, nitrite,acetate, ammonia and magnesium. The by-products are also commonlyreferred to as “de-sugared” solutions.

“Black liquor” refers to the liquor resulting from the sulfate or kraftpaper processes. Black liquor comprises lignin and tall oil.

“Tall oil” refers to a mixture of rosin acids, fatty acids includingoleic and linoleic acids and other organic material including sterolsand long chain alcohols resulting from acid treatment of black liquor asdescribed above.

“Triglycerides” refers to esters of glycerol, a trihydric alcohol, withdifferent fatty acids of varying molecular weight associated with aparticular fat or oil. Triglycerides are the principal components ofanimal fats and vegetable oils. The most common fatty acids sourced fromnatural fats and oils include palmitic, stearic and linoleic acid.

“Fatty acids” means carboxylic acids derived from or contained in ananimal or vegetable fat or oil. Fatty acids comprise a terminal COOHgroup and a long chain saturated or unsaturated alkyl chain.Representative fatty acids include butyric acid, lauric acid, palmiticacid, stearic acid, oleic acid, linoleic acid, linolenic acid, and thelike.

“Glycerin” and “glycerol” means 1,2,3-propanetriol.

Glycerin and fatty acids can be derived as by-products fromtransesterification reactions involving triglycerides includingtransesterification reactions involving biodiesel manufacturingprocesses as described herein.

“Methyl esters” and “ethyl esters” means methyl and ethyl esters offatty acids as described herein.

“Vegetable oil” means triglycerides extracted from the seeds, fruit orleaves of plants including corn oil, soybean oil, canola oil, palm oil,coconut oil, rapeseed oil, and the like.

In an embodiment, methyl esters, ethyl esters, glycerin and fatty acidsare derived from transesterification reactions involving triglycerides.

“Transesterification reactions involving triglycerides” refers to thesplitting of triglyceride esters derived from vegetable oils and/oranimal fats in the presence of base and a monohydroxy alcohol such asmethanol or ethanol to produce monoesters of the fatty acids comprisingthe original triglycerides.

Representative fats and oils used in the transesterification reactionsdescribed herein include tallow, crude tall oil, virgin vegetable oils,soy, mustard, canola, coconut, rapeseed, palm, poultry offal, fish oils,used cooking oils, and/or trap grease, and the like.

In an embodiment, the glycerin, fatty acids, ethyl esters and methylesters are derived from a biodiesel manufacturing process.

Biodiesel is a cleaner-burning diesel replacement fuel made fromnatural, renewable sources. For example, biodiesel can include fattyacid alkyl esters used as a cleaner-burning diesel replacement fuel madefrom sources such as new and used vegetable oils and animal fats.

According to the American Fuel Data Center of the U.S. Department ofEnergy, approximately 55% of the biodiesel is currently produced fromrecycled fat or oil feedstock, including recycled cooking grease. Theother half of the industry is limited to vegetable oils, the leastexpensive of which is soy oil. The soy industry has been the drivingforce behind biodiesel commercialization because of excess productioncapacity, product surpluses, and declining prices. Similar issues applyto the recycled grease and animal fats industry, even though thesefeedstocks are less expensive than soy oils. Based on the combinedresources of both industries, there is enough of the feedstock to supply1.9 billion gallons of biodiesel.

Biodiesel is typically made through a chemical process calledtransesterification in which vegetable oil or animal fats are convertedto fatty acid alkyl esters and glycerin by-products. Fatty acids andfatty acid alkyl esters can be produced from oils and fats bybase-catalyzed transesterification of the oil, direct acid-catalyzedesterification of the oil and conversion of the oil to fatty acids andsubsequent esterification to biodiesel.

The majority of fatty acid alkyl esters are produced by thebase-catalyzed method. In general, any base may be used as the catalystused for transesterification of the oil to produce biodiesel, howeversodium hydroxide or potassium hydroxide are used in most commercialprocesses.

In the biodiesel manufacturing process, the oils and fats can befiltered and preprocessed to remove water and contaminants. If freefatty acids are present, they can be removed or transformed intobiodiesel using special pretreatment technologies, such as acidcatalyzed esterification. The pretreated oils and fats can then be mixedwith an alcohol and a catalyst (e.g. base). The base used for thereaction is typically sodium hydroxide or potassium hydroxide, beingdissolved in the alcohol used (typically ethanol or methanol) to formthe corresponding alkoxide, with standard agitation or mixing. It shouldbe appreciated that any suitable base can be used. The alkoxide may thenbe charged into a closed reaction vessel and the oils and fats areadded. The system can then be closed, and held at about 71° C. (160° F.)for a period of about 1 to 8 hours, although some systems recommend thatthe reactions take place at room temperature.

Once the reactions are complete the oil molecules (e.g. triglycerides)are hydrolyzed and two major products are produced: 1) a crude fattyacid alkyl esters phase (i.e. biodiesel phase) and 2) a glycerinby-product phase. Typically, the crude fatty acid alkyl esters phaseforms a layer on top of the denser glycerin by-product phase. Becausethe glycerin by-product phase is denser than the biodiesel phase, thetwo can be gravity separated. For example, the glycerin by-product phasecan be simply drawn off the bottom of a settling vessel. In some cases,a centrifuge may be employed to speed the separation of the two phases.

The glycerin by-product phase typically consists of a mixture ofglycerin, methyl esters, methanol, mong and inorganic salts and water.Mong is “matiere organique non glycerol”. Mong normally consists ofsoaps, free fatty acids, and other impurities. Methyl esters aretypically present in an amount of about 0.01 to about 5 percent byweight.

Methanol can be present in the glycerin and fatty acids in an amountgreater than about 5 weight percent to about 30 weight percent. Themethanol can be a valuable component in the alternative fuels because ofits low flash point which can help ignite the fuel.

In certain instances, it may be necessary to further refine the glycerinby-product prior to use, for example by washing, acidulation ordistillation to adjust the glycerin concentration and/or removeimpurities. Methanol may also be added to the desired concentration.

In an embodiment, the glycerin-containing by-product comprises about 30to about 95 weight percent of glycerin.

In an embodiment, the combustible solid is coal and the liquidhydrocarbon component is by-product glycerin.

The fatty acid by-products can originate from the refining of the crudefatty acid alkyl esters phase and/or the crude glycerin phase during thebiodiesel manufacturing process. For example, the crude fatty acid alkylesters phase typically includes a mixture of fatty acid alkyl esters,water and a fatty acid salts component. These fatty acid salts componentgenerally form a solution with the water phase (e.g. soap water) wherethey can be further separated from the fatty acid alkyl esterscomponent. Once separated from the fatty acid alkyl esters component,any suitable acid such as, for example, hydrochloric acid can be addedto the water phase containing the fatty acid salts component to producethe fatty acid by-products of the present invention.

The fatty acid by-product may be in a wax or solid form. It can alsocontain fatty acid esters. The esters are beneficial components in thealternative fuel mixture.

Similarly, the crude glycerin phase typically includes a mixture ofglycerin, water and a fatty acid salts component. This fatty acid saltscomponent forms a solution or suspension with the water phase where itcan be further separated from the glycerin component by adding anysuitable acid to recover the fatty acid by-products suitable for thepresent invention.

It should be appreciated that the fatty acid by-products of the presentinvention can be derived from the acidulation of any of the biodieselmanufacturing process streams/stages that contain the fatty acid saltscomponent (e.g. soap water) including, for example, the wash water.These fatty acid by-products derived from any of the differentstages/streams of the biodiesel manufacturing process can be used as acomponent in alternative fuel.

The alternative fuels are prepared by applying the desired amount ofliquid hydrocarbon component to the combustible solid, for example byspraying onto piles of the combustible solid or by means of showersoriented over conveyors used to transport the combustible solid. Ifdesired, the liquid hydrocarbon component-combustible solid mixture maybe mixed to ensure even distribution of the liquid hydrocarbon in thecombustible solid.

In the case of loose or finely divided combustible solids, thealternative fuel may be prepared by applying the liquid hydrocarboncomponent to the combustible solid and pressing the resulting materialinto briquettes or ingots.

In an embodiment, about 0.1 to about 49 weight percent of said liquidhydrocarbon component is applied to the combustible solid.

In an embodiment, about 0.1 to about 25 weight percent of said liquidhydrocarbon component is applied to the combustible solid.

The alternative fuel of this invention may be used as a substitute for,or additive to conventional combustible solids for combustion in boilersor furnaces.

Changes can be made in the composition, operation, and arrangement ofthe method of the invention described herein without departing from theconcept and scope of the invention as defined in the claims.

1. A alternative fuel comprising one or more combustible solids and oneor more liquid hydrocarbon components selected from a group consistingof sugar solutions, tall oil, black liquor, vegetable oils, animal fats,triglycerides, methyl esters, ethyl esters, glycerin and fatty acids,provided that when the liquid hydrocarbon component is vegetable oil,the combustible solid is other than a cellulosic powder and furtherprovided that when the combustible solid is coal, the liquid hydrocarboncomponent is other than sugar solutions.
 2. The alternative fuel ofclaim 1 comprising about 0.1 to about 49 weight percent of said liquidhydrocarbon components.
 3. The alternative fuel of claim 2 wherein thecombustible solid is selected from coal, wood chips, coke and garbage.4. The alternative fuel of claim 3 comprising about 0.1 to about 25weight percent of said liquid hydrocarbon components.
 5. The alternativefuel of claim 3 wherein the methyl esters, ethyl esters, glycerin andfatty acids are derived from transesterification reactions involvingtriglycerides.
 6. The alternative fuel of claim 3 wherein the methylesters, ethyl esters, glycerin and fatty acids are derived from abiodiesel manufacturing process.
 7. The alternative fuel of claim 3wherein the combustible solid is coal.
 8. The alternative fuel of claim3 wherein the liquid hydrocarbon is a glycerin-containing by-product ofthe biodiesel process comprising greater than about 5 to about 30 weightpercent methanol.
 9. The alternative fuel of claim 8 wherein theglycerin-containing by-product comprises about 30 to about 95 weightpercent of glycerin.
 10. A method of preparing a alternative fuelcomprising applying one or more liquid hydrocarbon components selectedfrom a group consisting of sugar solutions, tall oil, black liquor,vegetable oils, animal fats, triglycerides, methyl esters, ethyl esters,glycerin and fatty acids to one or more combustible solids, providedthat when the liquid hydrocarbon component is vegetable oil, thecombustible solid is other than a cellulosic powder and further providedthat when the combustible solid is coal, the liquid hydrocarboncomponent is other than sugar solutions.
 11. The method of claim 10wherein about 0.1 to about 49 weight percent of said liquid hydrocarboncomponents is applied to said combustible solids.
 12. The method ofclaim 11 wherein the combustible solids are selected from coal, woodchips, coke and garbage.
 13. The method of claim 12 wherein about 0.1 toabout 25 weight percent of said liquid hydrocarbon components areapplied to said combustible solids.
 14. The method of claim 11 whereinthe methyl esters, ethyl esters, glycerin and fatty acids are derivedfrom transesterification reactions involving triglycerides.
 15. Themethod of claim 11 wherein the methyl esters, ethyl esters, glycerin andfatty acids are derived from a biodiesel manufacturing process.
 16. Themethod of claim 11 wherein the combustible solid is coal.
 17. The methodof claim 16 wherein the liquid hydrocarbon is a glycerin-containingby-product of the biodiesel process comprising greater than about 5 toabout 30 weight percent methanol.
 18. The method of claim 17 wherein theglycerin-containing by-product comprises about 30 to about 95 weightpercent of glycerin.